HPV Testing Followed By Selective Use of Pap Test Detects Cervical Abnormalities
According to the results of a study conducted in Italy, use of HPV testing-followed by liquid-based cytology if the HPV test is positive-may offer an alternative approach to cervical cancer screening in women younger than 35 years of age. These results were published in the journal Lancet Oncology.
Human papillomaviruses (HPV) consist of more than 100 different viruses. Some types of HPV cause warts on the hands or feet; others cause genital warts; and some have been linked with cancer, most notably cervical cancer. The types of HPV most commonly linked with cervical cancer are HPV 16 and HPV 18, but several other high-risk types contribute to cancer as well.
The recognition that specific types of HPV are the cause of cervical cancer led to the development of a vaccine against four common types of HPV and a test to identify infection with several high-risk types of HPV.
An important use of HPV testing is for further evaluation of women with an indeterminate Pap test result. For women over the age of 30, HPV testing may also be used for initial cervical cancer screening in combination with a Pap test. Thus far, use of HPV testing for initial screening of younger women has generally not been recommended because many young women will have HPV infections that will clear without causing cervical abnormalities.
To explore a broader use of HPV testing in younger women, researchers in Italy evaluated two approaches to cervical cancer screening in women under the age of 35. Women were assigned to receive either conventional cervical cancer screening (a standard Pap test followed by colposcopy if the Pap test results were abnormal), or an alternative approach consisting of a combination of HPV testing and liquid-based cytology, with referral to colposcopy if the cytology results were abnormal. In liquid-based cytology, cervical material that is removed by the spatula or brush is rinsed in liquid. The liquid is then processed to isolate the cells that need to be analyzed. These cells are spread in a thin layer on a slide and viewed under a microscope.
- The alternative approach to screening detected more cervical abnormalities than the conventional approach.
- A limitation of the alternative approach is that it more frequently indicated that cancer was present when it actually was not (false-positive result).
- Compared to HPV testing alone, the simultaneous use of HPV testing and liquid-based cytology did not significantly increase detection of cervical abnormalities, but did increase false-positive test results.
The researchers concluded that HPV testing followed by selective use of liquid-based cytology may be a feasible alternative to conventional cervical cancer screening in young women. The researchers note that longer follow-up will provide additional information about the value of this approach.
Reference: Ronco G, Giorgi-Rossi P, Carozzi F et al. Human Papillomavirus Testing and Liquid-based Cytology in Primary Screening of Women Younger than 35 Years: Results at Recruitment for a Randomised Controlled Trial. Lancet Oncology. 2006;7:547-555.